Thermostatically-controlled rotary switch



R. D. SMITH.

THERMOSTATICALLY CONTROLLED ROTARY SWITCH. APPLICATION FILED SEPT. 12, I916. RENEWED JUNE 11, 1919.

2 SHEETSSHEET I.

Patented Mar. 16, 1920.

R. D. SMITH. THERMOSTATICALLY CONTROLLED ROTARY SWITCH. APPLICATION FILED SEPT-12,1916. RENEWED JUNE 11, 1919. 1,334,181 Patented Mar. 16, 1920.

2 SHEETS-SHEET 2- UNITED STATES PA ENT orrucn.

RAYMO D n. SMITH, 0F ARLINGTON, MASSACHUSETTS, ASSIGNQR To TREMoNT PRonUCTS COMPANY, OF BOSTON, MASSACHUSETTS, A CoRPoRATIoN or MASS CHUSETT THERMOSTATICALLYrCONTROLLED ROTARY SWITCH.

Specification of Letters Patent.

Patented Mar.1'6, 1920.

Application filed September 12, 1916, Serial No. 119,757. Renewed June 11, 1919. Serial No. 303,478.

Arlington, in they county of Middlesex and 'State of Massachusetts, have invented certain new and useful Improvements 1n Thermostatically-Controlled Rotary Switches,

of which the following is a specification.

My invention relates to rotary switches for the control of electric circuits and specifi cally to that form of rotary switch adapted by progressive stagesof rotation to alternately make and break a circuit.

The object of my invention is to provide in such a switch, improved thermostatically controlled detent means which shall act normally to restrain the rotatable contact element in a circuit closing position when manual actuation is effected as normally adapted to open the circuit, and to provide means operated by the usual manual actuating instrumentality, thereby to render active a normally inactive and denergized device for heating the thermostat, for'causing a delayed automatic release of the said contact element from its restraining detent.

, Other objects of my invention reside specifically in improved details of construction and arrangement of the thermostatically controlled detent;while .novel and ad vantageous arrangements of parts, afiording compactness and durabilty, will be evident from the following description and from the drawings hereof.

In the drawings, Figure 1 is an enlarged Vertical section'taken through the switch on the plane 1'1 of Fig. 2; Fig. 2 is a plan View of the switch Showing the movable contact clips in theirfcircuit closing posi tion; 'Fig'. 3' is a diagrammatic view showing the operation of my improved detent device and controlling thermostat; Fig. 4 is 'a view in perspective, showing the actuating shaft and its carried parts; Fig. 5 is a diagram of electricalconnections; Fig. 6 is a plan view similar to Fig. 2 showing the lead wires and their respective connections; Fig. 7 is a partial view of certain detent parts and of the cam actuated sliding dog taken partly in section on the horizontal plane 77 in Fig. 1; Fig. 8 is a view taken partly 8 8 in Fig. 1 showing the auxiliary contacts open; Fig. 9 is a plan view ofthe contact clips in their circuit opening position; Fig.

'10 shows a detail of construction and is taken in section on the plane 7-7 in Fig. l, the actuating shaft and carn'carried thereby being shown advanced 90 and the main contact-carrying structure thereby freed from engagement with the stationary ratchet wheel to permit tension caused follow-up movement of said structure relative to the shaft; Fig. 11 is a sectional view similar to Fig. 8, showing the auxiliary contacts closed.

Throughout the drawings and in the following description, similar parts are designated by like numerals.

in sectionon the horizontal plane with a lower bearing 19 and an upper bearing 20 which bearings are contained in bracket plates 21 and 22 respectively the said bracket plates being fixed to the lower and upper surfaces respectively of the insulating base 10. In Fig. 4 it is clearly shown that the shaft 8 fixedly carries acollar 24, a cam 25 and at its lower extremity an auxiliary contact clip structure composed of the detent plate 26 and the conductive clips 27 insulated therefrom. A spring 28,

loosely coiled about the shaft -l8, engages with a notch 29,-in the collar 24 and with the plate 17 for establishing a tensioned connection between the shaft 18 and the main contact clip structure. The usual sliding dog plate 30, by engagement of its projection 31 with a stationary ratchet wheel 32, op-

poses the action of spring 28 but is manually releasable from such opposing engagement by the action of cam 25 in the elongated slot 33 of the dog plate 30 when suitable tension has been established to break the circuit)this type of switch construction for producing quick break of the gage the portions 34 by means of a small shown in Fig; 3.

spring 37 It will be evident however that the arrangement of parts is such that strong enough rotative tendency of the detent plate 17 would be operative to effect release from the detent lever against the action of spring 37. Such release however is prevented normally by a projecting plate 38 made fast to the inner surface of a bimetallic thermostat 39 which thermostat at one end is securely anchored to the upper' bracket plate 22 and which at the other end is formed inwardly to engage with a roller abutment, 41. The roller 41 without frictionally opposing the heat caused movement of the thermostat (which is in this case of a straightening nature or generally outbending) substantially reinforces the ther mostat against the thrustimparted to it by the lever .35. The relative releasing movements of these detent parts are clearly Carried by the a detent spring which engages the detent plate 26 upon actuation of key shaft 18 to open the circuit, and which by such engagement acts cooperatively-with the detent lever 35 to establish a tensioned relation be-.

tween the shaft 18 and the main clip structure in an obvious manner, so that upon thermostatically caused release of the lever 35, the clip structure will be rotatively advanced, automatically tobreak the. circuit by the tension in spring 28.

Such delayed release of the lever. 35 is caused by connecting into circuit the resistive, heating winding 42 (which is carried by and insulated from the thermostat) by means of the auxiliary clips 27 which clips move with the shaft 18 to make such to release the detent lever 35.

appears at 45 and an indicator dial at 46 circuit between the auxiliary contact blades 43, 43 as shown in Figs. 8 and 11. The thermostat is thereby energized and after a time interval moves as indicatedin Fig. 3 A casing carried by the shaft 18 and therefore movable with the controlling button 47 thereby lower bracket plate 21 is indicating the on position of the switch" and the position of the shaft 18 when actuated and held for causing delayed automatic opening of the circuit.

Although I have described my invention herein as comprising a rotary switch embodying my improved arrangement of thermostatically controlled detent mechanism, it

willbe appreciated that the novel andad-- vantageous features embodied in the details of this mechanism are applicable to the control of any tension-actuated device or member, and it will further be apparent that material departure may be made from the exact structural arrangement herein disclosed, and still avail of the new and useful application of principles shown by the invention. For instance, the detent lever 35 need not necessarily be pivoted to a stationary frame portion but may be carried by the tension-actuated member itself (in this case the cam plate 17), as is illustrated and described in my copending application, Serial No. 165,026, where the tension-actuated member isembodied as the stem of a rot-atable gas valve. Certain of the appended claims, accordingly, are not limited-to my invention as embodied specifically .in an electric switch; but are intended to define the'broadly novel means by which a simple flexing thermostat may be rendered efiiciently operative for heavy duty.

The mechanical principles involved in the thermostatic detent herein disclosed are such that a relatively heavy circuit opening spring may be employed and be satisfac-' torily controlled by a necessarily thin and limber thermostat, incapable in itself of producing much powerfor overcoming frictional resistance to the disengagement'of a restraining detent.

Having thus described herein an illustrative embodiment of my 'present invention, and without limiting the scope thereof to such precise embodiment what I claim is:

LA thermostatically controlled device comprising, in combination; a rotatable member adapted to betensioned for unidirectional movement; a bell-crank lever being such that said thrust tends to displace the thermostat and detent in a direction approximately similar'to that of the designed thermally caused movement thereof.

2. A thermostatically controlled device comprising,

positioned on a pivot operatively at one end.

to intercept said member and upon movement to release said member, with spring means operatively arranged to restore said lever to its intercepting position ;and a bimetallic resilient thermostat, having a pro jecting detent mounted thereon, and positioned normally so that said detent engages said lever at the opposite end and is opera tive to hold the latter in said intercepting position,-the position of said pivot relative to the direction of thrust of said member on said lever, and of said lever of said dotent, being such that said thrust tends to displace the thermostat and detent in a direction approximately similar to that of the designed thermally caused movement thereof, together with a reinforcing arrangement for said thermostat embodying, with a cooperative conformation of a free part of the thermostat, a stationary antifrictional support positioned to be engaged thereby when said member engages said lever, the cooperative arrangement and position being such that designed thermallycaused movement of said thermostat is operatively unconstrained by said support and such that the lines of pressure of said thermostat on said support and of said lever on said spur detent are substantially parallel.

3. The combination with a tension-actuated member of thermostatically controlled detent mechanism for governing the movement thereof, embodying a movable detent element having a constraining support, arranged normally in operative relation to said member, and adapted to yield for permitting said movement thereof; a movable stop arranged in one position thereof to intercept said element and to resist the said yielding thereof; and an abutment-supported, flexing thermostat, having operative connection to said stop whereby thermally-caused fiexure in said thermostat retracts. saidstop from engagement with said element,the cooperative formation and positioning of said member, said element with its support, and of said stop, being such that a component only of the thrust imposed by said member upon said element is. borne by said stop and is rendered operative to assistthermostatio retraction of the latter. 7

. 4. The combination with a tension-actuated member of thermostatically controlled detent mechanism for governing the movement thereof, embodying a pivoted lever normally arranged in operative relation to said member and adapted to yield about its pivot for permitting said movement of the member; a movable stopv arranged in one position thereof to intercept said lever and to resist the said yielding thereof; and

an abutment-supported, flexing thermostat,

having operative connection to said stop whereby thermally-caused flexure in said thermostat retracts said stop from engagement with said lever,the cooperative for- 'mation and positioning of said member,

said lever with its pivot, and of said stop, being such that a component only of the thrust imposed by said member upon said lever is borne by said stop, and is rendered operative to assist retraction of the latter by the thermostat. I

5. The combination with a tension-actuated member of thermostatically controlled detent mechanism for governing the movement thereof, embodying a pivoted lever normally positioned in the path of movement of said member and adapted to yield therefrom about its pivot for permitting said movement of the member; a movable stop arranged'in one position thereof to intercept said lever and to resist the said yielding thereof; and an abutment-supported, flexing thermostat, having operative connection to said stop whereby thermally-caused flexure in said thermostat retracts said stop from-engagement with said lever, the cooperative formation and positioning of said member, said lever with its pivot, and of said stop, being such that a component only .of the thrust imposed by said member upon said lever is borne by said stop, and is rendered operative to assist retraction of the latter by the thermostat. 6. The combination with a tension-actuated member of thermostatically controlled detent mechanism for governing the movement thereof, embodying .a pivoted lever normally positioned by resilient means to intercept said member and adapted to yield about its pivot and retreat from said intercepting position when engaged by said member, thereby to permit said movement of the latter; a movable stop arrangedin one position thereof to intercept said lever and to resist the said yielding thereof; and an abutment-supported, flexing thermostat, having operative connection to said stop whereby thermally-caused flexure in said thermostat retracts said stop from engagement with said lever,the cooperative formation and positioning of said member, said lever with its operative formation and'positioning of said member, said lever with its pivot, and of" said stop, being such thata component only of the thrust imposed by said member upon said lever is borne by said stop, and is rendered operative to assistretraction of the latter by the thermostat.

. 8. The combination with a tension-actuated member of thermostatically controlled detent mechanism for governing the movement thereof, embodying a pivoted lever normally arranged in operative relation to said member and adapted to yield about its pivot for permitting said movement of the member; a movable stop arranged in one position thereof to intercept said lever-and to resist the said yielding thereof; and a, bimetallic, flexing thermostat, abutment-supported at one end thereof and at a free portion provided with operativeconnection to said stop whereby thermally-caused flexure in said thermostat retracts said stop from engagement with said lever',the cooperative formation and positioning of said member, said lever with its pivot, and of said stop, being such that a component only of the thrust imposed by said member upon said lever isborne by said stop and thermostat, and thereby assists the latter to retract the former as said. i

v 9. The combination with a tension-actuated member of thermostatically controlled detent mechanism for governing the movement thereof, embodying a pivoted lever normally arranged in operative relation to said member and adapted to yield about its pivot for permitting said movement of the member; a movable stop arranged in one( position thereof to intercept said lever and to resist the said yielding thereof; and a bimetallic, flexing thermostat, abutmentsupported at one end thereof, carrying at a free" portion thereof said'stop, and adapted I by thermally-caused flexure to retract the latter from engagement with said lever,-- the cooperative formation and positioning of said member, said lever with its pivot,

' and of said stop, being such that a component only. of thethrust imposed by said vmember upon said lever is borne by said stop and thermostat, and thereby assists the latter 'to retract the former assaid.

.10. The combination with a tension-actuated member of thermostatically controlled detnt mechanism for overning the movement thereof, embodying a pivoted lever normally arranged in operative relation to said member and adapted to yield about its pivot for permitting said movement of the member; a movable stop arranged in one position thereof to intercept said lever and to resistihe said yielding thereof; and .a bimetallic, flexing thermostat, abutmentsupported at one end thereof, carrying. at a free portion thereof said stop, and adapted by thermally-caused flexure to retract the latter from engagement with said lever, the cooperative formation and positioning of said member, said lever with its pivot, and

of said stop, being such that the thrust imposed by said member upon said lever is borne in part by said pivot and in part by said stop and thermostat, and thereby assists the latter -to retract the former; together with a constraining abutment for the free end of said thermostat, so formed and positioned relative there-to that the thermostat is reinforced thereby against mechanical flexure due to said thrust, but'is unrestrained thereby in thermally-caused movement. g

lL'In an electric switch including a r0- tary contact member adapted alternatelyto make and breaka circuit and a spring connected, manually operable device for actuating the same, in combination; an insulated vprojection extending radially from said contact member, a pivoted detent-lever normally positioned in the path of movement of said projection, and adapted to yield therefrom about its pivot for permitting tension-caused circuit controlling movementtof said memher; a movable 'stopiarranged in one position thereof to intercept said lever and -to resist the said yielding thereof ,3 and an abutmentmounted, flexing thermostat, having operative connection to said stop whereby thermal energization of said thermostat retracts said stop from engagement with said lever; together with an electric heating unit for thermally energizingthe thermostat.

12.- In an electric switch including a rotary contact member adapted alternately to make and break a circuit and a spring connected, manually operable device for actuating the same, lated projection extending radially from said contact member, a pivoted detent lever normally positioned in the path of move,- ment of said projection, and adapted to yield therefrom about its pivot for per- 120 mitt-ing tension-caused, circuit-controlling movement of said member; a movable stop arranged in one position thereof :to intercept said lever and to resist the said yield-' ing thereof; and an abutment-mounted, 125

- flexing thermostat, having operative connecin combination; an insuprojection, said lever with its pivot, and of said stop, being such that a component only of the thrust imposed by said projection on lever is borne by said stop, and is rendered operative to assist retraction of the latter by the thermostat, and an electric heating unit for thermally energizing the thermostat.

Signed at Boston, Massachusetts, this eleventh day of September, 1916.

' RAYMOND D. SMITH.

Witnesses:

C. D. LAXXIXG, Jams D. GORDON. 

